The present invention relates to liquid formulations containing one or more cationic compounds, such as: liquid fabric softeners of the type conventionally employed in the rinse cycle of automatic clothes washing machines; liquid textile softeners used for fabric finishing; compositions used in the paper industry for debonding and softening of paper fibers; hair and skin conditioners; compositions applied to clay-based products such as drilling muds to make them hydrophobic; and many other uses.
The present invention relates more particularly to novel compositions for liquid cationic formulations, wherein the ingredients of the composition contribute significantly to the ease of formulation, stability, dispersibility, fluidity and the performance properties of the compositions.
Cationics have achieved widespread usage because of their ability to impart to fabric, (i.e. articles of clothing, textiles, and so forth), paper, hair, and many other substrates, properties including softness to the touch, ease of handling, increased lubricity, and a reduced tendency to carry or pick up static electricity. One form in which cationics are provided is as a liquid, for instance as an emulsion or as a solution/suspension of the desired components. An appropriate controlled amount of the liquid cationic formulation is employed (poured into the washing machine or textile bath in which the fabric is being washed or rinsed; or applied to the hair; or added to the head tank of the paper making machine, or otherwise depending on the application).
Typically, in the case of liquid fabric softeners it is provided during the rinse cycle of the washing machine, either poured in by hand or metered in by an appropriate automatic metering device with which the washing machine is equipped. In the same vein, cationics (typically dialkyl quaternaries) are used in textile mills to add lubricity and finishing to the fabric prior to shipping the textile to market. The mill applies the cationic formulation in dilute emulsions and rapidly dries the excess water from the fabric. The fibers are thus lubricated and given a surface finish. Hair conditioners are applied as dilute cationic emulsions to the hair following its wash. Adding these conditioners (typically dialkyl quaternaries) reduces the tendency for tangling, improves the manageability, and imparts a soft feel to the hair strands. In the papermaking process, cationics called debonders are generally quaternary salt emulsions in water. These are added to the head tank wherein the dilute fibers are conditioned with the debonders just prior to being fed onto the papermaking screen. These debonders give improved softness feeling to the paper fibers. In all cases the cationics are added to hot water to make an emulsion, and then added to the substrate in water or added to the substrate in water or added as a high solids concentrate to the substrate, to impart softness, lubricity, antistatic properties, ease of handling of the substrate and to improve surface appearance.
It is believed that the user finds it to be desirable that the liquid cationic formulation is in the form of a moderately viscous fluid, rather more viscous than water yet still capable of flowing under its own weight. Thus, for instance, having a formulation that at solids concentrations of less than 5% exhibit viscosities greater than 100 cps which would be effective in softening and disperse readily in cold water, such as the present invention, would be desirable in the marketplace. In other cases, the industrial user may want less viscous, fluid emulsions or concentrates that disperse easily, with fine particle sizes.
In the case of fabric softeners, formulations which would be low melting (compared to many softener raw materials which must be heated to 90-120.degree. F.) and are easily dispersed in room temperature water would save time and money in both equipment and production costs.
High solids formulations (or "ultras") which have solids contents greater than 20% have seen large commercial success over the last five years. The drive to increase solids contents, and to reduce handling and transportation costs is becoming ever more important. The desire ultimately to form a clear, highly active, high performance product when the product is dispersed in water is becoming an important objective. The standard emulsion type fabric softener ultras in the market suffer from thickening problems following production, causing reduced dispersibility in the rinse cycle.
There is a need for cationic formulations, including fabric softeners, which are nonflammable yet easy to handle and disperse in room temperature water. Most quaternary formulations contain isopropanol or ethanol as solvents in order to aid in production and handling. However, volatile solvents such as these are becoming an important environmental issue in states including California and Florida. Thus, a different technique for achieving fluidity and good dispersiblity, while avoiding the use of volatile solvents, is needed. Also, as interest grows in dilutable concentrated product which can be diluted by the customer (e.g. by 3-10 times) to make a regular (2-10%) concentration of the product as used, the need for making such products that are easily dispersible without resort to volatile or flammable solvents is very important.
Thus, there is still a need in this field for liquid cationic formulations which can be prepared more readily without encountering difficulties such as those described above, and are more concentrated and disperse easily in cold water. There is also a need in this field for cationic formulations which can be manufactured as concentrates, wherein formulators can produce consumer and industrial products easily, quickly and effectively with minimal equipment and heating requirements. There is also a need for products (especially for use in the textile and paper areas) which are not flammable but which avoid the handling and viscosity problems posed by the conventional less flammable substitutes such as propylene glycol, diethylene glycol and the like.
The prior art concerning various cationic compositions is extensive, yet has not taught or suggested the considerable and unexpected benefits that are provided by the formulations which correspond to the present invention. For instance, U.S. Pat. No. 5,399,272 discloses a clear or translucent liquid fabric softening composition containing any of certain ester-quaternary cationic compounds. The disclosure also requires any of certain alcohols, glycols, esters or ethers as solvent.
However, the disclosure of U.S. Pat. No. 5,399,272 also requires a second quaternary compound and/or an amine oxide to serve as a dispersibility aid. The requirement for this dispersibility aid serves as a teaching that the disclosed solvent system does not adequately provide needed dispersiblity on its own, that is, in the absence of a dispersibility aid. This teaching thus serves to confirm the present state of the art, namely, that there remains a need for formulations which serve to solubilize and disperse cationic active agents without needing to resort to the addition of dispersibliity aids. After all, extra dispersiblity aids will add to the cost of materials, and having to add another cationic to the formulation could in some cases interfere with obtaining desired fluidity, maintaining a monophasic state, or obtaining the desired performance properties.
The present invention satisfies the needs identified above, and provides as well additional advantages that will become apparent in the following description.